This invention relates to the technical field of a digital image recording apparatus.
Heretofore, the image recorded on photographic films such as negatives and reversals (which are hereunder referred to simply as "films") has been commonly printed on light-sensitive materials such as photographic paper by means of direct (analog) exposure, in which projected light from the film is allowed to be incident on the light-sensitive material to achieve its areal exposure.
A new technology has recently been introduced and this is a printer that relies upon digital exposure. Briefly, the image recorded on a film is read photoelectrically, converted to a digital signal and subjected to various image processing operations to produce image data for recording purposes; recording light that has been modulated in accordance with the image data is used to scan and expose a light-sensitive material to record a latent image, which is subsequently developed and output as a print (photograph). The printer operating on this principle has been commercialized as a digital photoprinter.
In the digital photoprinter, the image on a film is read photoelectrically and gradation correction and other operations are performed by subsequent image (signal) processing to determine exposing conditions. Hence, the digital photoprinter has many capabilities in image processing such as editing of printed images by, for example, assembling a plurality of images or splitting a single image into plural images, as well as color/density adjustment and edge enhancement; as a result, prints can be output after various image processing operations have been performed in accordance with specific uses. In addition, the data on a printed image can be supplied into a computer or the like and stored in recording media such as a floppy disk.
A further advantage of the digital photoprinter is that compared to the prints produced by the conventional method of direct exposure, those which are output by the digital photoprinter have better image quality in such aspects as resolution and color/density reproduction.
Having these features, the digital photoprinter is basically composed of an input machine having a scanner (image reader) and an image processor and an output machine having both an exposing device and a developing device.
In the scanner, reading light issuing from a light source is allowed to be incident on a film, from which projected light carrying the image recorded on the film is produced and focused by an imaging lens to form a sharp image on an image sensor such as a CCD sensor, the image being then captured by photoelectric conversion and sent to the image processor as data for the image on the film (i.e., the image data signal). In the image processor, the image data sent from the scanner are subjected to specified image processing operations and the resulting output image data for image recording (i.e., exposing conditions) are sent to the exposing device.
In the exposing device, if it is of a type that relies upon exposure by scanning with an optical beam, the latter is modulated in accordance with the image data sent from the image processor and deflected in a main scanning direction as the light-sensitive material (e.g. photographic paper) is transported in an auxiliary direction perpendicular to the main scanning direction, whereby a latent image is formed as the result of scan exposure (printing) of the light-sensitive material with the optical beam and a back print is also recorded. In the developing device (processor), the exposed light-sensitive material is subjected to development and other specified processing operations so as to output a print which reproduces the image that has been recorded on the film.
In the exposing device, whether it is in the digital photoprinter or an ordinary photoprinter that relies upon "direct" exposure, a virgin light-sensitive material is in the form of a magazine, i.e., a roll contained in a lightproof case. The light-sensitive material is withdrawn out of the magazine in the exposing device and further transported for exposure and other necessary steps.
In the ordinary photoprinter, the light-sensitive material being transported is not cut but remains a web as it is subjected to exposure, back print recording, development, rinse, drying and other necessary steps and only after these steps are complete, the light-sensitive material is cut to individual prints of a specified length. This process requires that frame information (frame perforations) for delineating individual frames (or prints) be formed before or after the exposure of the light-sensitive material. However, the portion of the light-sensitive material where the frame information is formed is simply a waste of space. In addition, frame information have to be formed by special means having a punch, a sensor or the like.
In the exposing device of a digital exposure type, the light-sensitive material in the process of exposure must be transported for scanning in high precision and without stops in order to record images of high quality that are free from unevenness and other defects. On the other hand, the transport of the light-sensitive material has to be stopped at the time of forming frame information and, in addition, the recording of back prints will fluctuate the load in the transport of the light-sensitive material for scanning.
In order to avoid these difficulties, the exposing device in the digital photoprinter is adapted to make a slack (loop) out of the light-sensitive material which is located not only between the exposing position and the frame information forming zone but also between the exposing position and the back print recording zone. If this approach is taken, the volume of the light-sensitive material in loop (the number of frames) must be controlled, the timing of exposure must be properly adjusted and there are many other factors including the complexity of the transport zone and in the control of the light-sensitive material; as a result, the equipment cost and the running cost increase inevitably.
Under the circumstances, an exposing device is desired that can be incorporated in a digital photoprinter and which is capable of exposing a light-sensitive material after it is cut to sheets corresponding to individual prints to be finally produced.
However, the digital exposing device which is capable of exposing a light-sensitive material after it is cut to sheets has not been actually realized yet.
In order to realize an inexpensive, compact and yet efficient exposing device, the pathlength, or the length over which the light-sensitive material emerging from its magazine is transported to the developing machine, is desirably shorter. However, no efficient digital exposing device having a short pathlength has been realized that is suitable for exposure to be performed after a light-sensitive material is cut to individual sheets.